Possible explanation for missing satellite galaxies in Dark Mattertheory

Dark Matter theory suggests that thousands of dwarf satellite galaxies
should be orbiting the Milky Way and other massive galaxies, but only 20
have been found so far. This was a bit of a black eye for DM theory, as
the number of satellite galaxies seen so far is more consistent with
modified gravity theories. This new simulation might explain the
discrepancy.

Yousuf Khan

Dark Matter Helped Early Galaxies Survive "Massacre"
"This model, recently presented at the Royal Society 2009 Summer Science
Exhibition in London, could explain the Milky Way's "missing satellite"
problem, said astrophysicist Andrew Benson of the California Institute
of Technology.

So far, astronomers know of only about 20 satellite galaxies of the
Milky Way, but according to a key theory of galaxy formation, there
should be thousands.

That's because big galaxies like the Milky Way are thought to have
formed through the violent mergers of many smaller galaxies.

Any discarded remnants that didn't make it into the larger structure
would have become satellite galaxies.

But if the new model is correct, then the Milky Way's "missing"
satellite galaxies never formed in the first place, said Benson, who was
not involved in the new study.

"Professor Frenk has shown that if you can prevent the formation of
galaxies very early in the universe, you can reduce the number of
galaxies that you would expect to see around the Milky Way down to a
level that is more compatible with what we actually observe." "
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